Novel Random High-Frequency Square-Wave and Pulse Voltage Injection Scheme-Based Sensorless Control of IPMSM Drives

Signal injection-based sensorless control schemes for interior permanent magnet synchronous machine (IPMSM) drives at zero and low speed are generally troubled by the audible noise induced by the fixed-frequency injected signals and the control performance sensitive to voltage distortions. Aiming at that, a novel random high-frequency square-wave and pulse voltage injection (RHFSPVI) with novel signal demodulation method-based sensorless control of IPMSM drives is proposed. First, the power spectra density (PSD) analyses of conventional high-frequency square-wave voltage injection (HFSVI) and high-frequency pulse voltage injection (HFPVI) methods are carried out. On the basis of the analysis results, the simple form of random square-wave and pulse voltage injection is analyzed and designed to eliminate discrete harmonics in the current PSD spectrum for the audible noise reduction. Moreover, a signal demodulation scheme matched with the proposed injected form is designed to prevent the impact of voltage distortions on the position estimation accuracy. The capability of the proposed sensorless control scheme is verified on a 750-W IPMSM drive platform.